Sweatshirts are arguably a type of sweater, but made of a fabric and cut similar to sweatpants. A sweatshirt is a variation of a sweater intended for sport or casual wear. It is fashioned out of a thick, usually cotton jersey material, as opposed to a knit textile. Sweatshirts are also almost exclusively casual attire, and not semi-formal as some other sweaters may be. Sweatshirts may or may not have a zipper.